Catalyst for purifying exhaust gas

摘要

PROBLEM;The present invention is directed to provide a catalyst for purifying exhaust gas capable of maintaining a superior catalytic performance even when the catalyst is exposed to an exhaust gas at a high temperature of 800° C. or higher.;SOLUTION;The catalyst for purifying exhaust gas of the present invention comprises a catalytically active component containing a noble metal and a promoter containing an oxygen storage material both being supported on a carrier. The oxygen storage material comprises cerium, zirconium, and iron, and content of iron in the oxygen storage material is 0.01% by mass or more and less than 0.70% by mass (Fe2O3 conversion) relative to the total mass of the oxygen storage material. And the oxygen storage material is (a) a complex oxide or a solid solution of iron and a metal comprising cerium and zirconium; or (b) an iron is supported on a complex oxide or a solid solution of a metal comprising cerium and zirconium.

主权项

1. A catalyst for purifying exhaust gas comprising at least two catalyst layers laminated on a carrier, at least one of the catalyst layers having a catalytically active component containing a noble metal and also having a promoter component containing an oxygen storage material, wherein:
the oxygen storage material comprises cerium, zirconium and iron; the content of iron in the oxygen storage material is 0.01% by mass or more and less than 0.70% by mass (calculated as Fe2O3) relative to the total mass of the oxygen storage material; and the oxygen storage material is (a) a complex oxide or a solid solution of iron, cerium, and zirconium; or (b) an iron supported on the surface of a complex oxide or a solid solution of cerium and zirconium; and wherein different noble metals are arranged in different layers of the at least two catalyst layers.